Rock-type units from USGS
Here’s a geology map for field navigation in more accessible portions of the Greater Chilkat Watershed—US side only. This geopdf is an interim product, to be updated as we ground-truth it.
My draft chapter in the GCW Atlas gives background on rock types, faults, geologic terranes, etc. My adaptation for geopdf preserves the code abbreviations shown here, adding brief list of the unit’s dominant rocks, and a field for time-period: capital letters in these codes.